Functionalization of yogurts with Agaricus bisporus extracts encapsulated in spray-dried maltodextrin crosslinked with citric acid

Abstract

A B S T R A C TMushroom extracts contain bioactive compounds potentially useful to functionalize foodstuffs. Herein, alcoholic extracts of Agaricus bisporus were studied for their bioactivity and viability as functional ingredients in a food product with high water content (yogurt). Extracts were microencapsulated (to improve their stability and hydrophilicity) by spray-drying, using maltodextrin crosslinked with citric acid as encapsulating material. The effect of thermal treatment (after atomization) on crosslinking and bioactivity of microspheres was tested. The incorporation of free and thermally untreated forms resulted in yogurts with higher initial antioxidant activity (EC 50 values: 214 and 272 mg.mL −1 ) that decreased after 7 days (EC 50 values: 248 and 314 mg.mL −1 ). Contrarily, thermally treated microencapsulated extracts showed higher antioxidant activity after the same period (EC 50 values, 0 days: 106 mg.mL −1 ; 7 days: 48.7 mg.mL −1 ), in result of an effective protection provided by microencapsulation with crosslinked maltodextrin and citric acid. Functionalized yogurts showed an overall maintenance of nutritional properties.

Spray-dried Spirulina platensis as an effective ingredient to improve yogurt formulations: Testing different encapsulating solutions

“…Overall, YSMA turned out to be the best solution to incorporate S. platensis in yogurt as it maintained nutritional and fatty acid profiles, provided a more appealing colour and, most of all, improved the antioxidant activity at a greater extent. In the study carried out by Francisco et al (2018), the incorporation of Agaricus bisporus extract encapsulated in maltodextrin crosslinked with citric acid in yogurts, increased the antioxidant activity (throughout 7 days of storage). This effect can be justified by the effective reaction of maltodextrin with citric acid providing effective crosslinking.…”

“…Samples were stored (4°C) protected from light for further analysis. All standards and reagents used were acquired from common sources as previously described (Francisco et al, 2018).…”

“…The microencapsulation process of spirulina was carried out using maltodextrin (MD) or maltodextrin cross-linked with citric acid as encapsulating materials, named SM and SMA samples respectively. The crosslinking reaction involves the reaction of hydroxyl groups from maltodextrin with carboxylic groups from citric acid (esterification reaction), and it was performed by spray drying process, according to the methodology developed by Francisco et al (2018). A blank of SMA sample was also prepared (MA) consisting of MD crosslinked with citric acid, but without S. platensis.…”

“…Thermogravimetric analysis (TGA). TGA was performed on a NETZSCH equipment (TG 209 F3 Tarsus, Selb, Germany) (Francisco et al, 2018). The base materials (maltodextrin, citric acid and S. platensis) and the produced microspheres (SM, SMA and MA) were heated (30°C to 600°C, at 10°C/min) in alumina crucibles (6-8 mg), under a nitrogen flow.…”

“…Moreover, when combined with citric acid and after thermal heating, it forms a polymeric network (crosslinking) due to the esterification reaction between the hydroxyl groups of maltodextrin and the carboxyl groups of citric acid (Castro-Cabado, Parra-Ruiz, Casado, & San Román, 2016). In addition to increasing the thermal and mechanical resistance (Castro-Cabado, Casado, & San Román, 2016b), these crosslinking reactions preserve the bioactivity of the encapsulated agents (Francisco et al, 2018).…”